Single crystal growth and photoelectrochemical study of copper tungstate

Single crystals of copper tungstate have been grown by employing double-decomposition chemical reaction between cupric chloride and sodium tungstate taken in the ratio 3:1 at 1000 degrees C, followed by slow and controlled/programmed cooling up to 600 degrees C. The kinetics of crystallization have been investigated at 800 and 850 degrees C by arresting the growth at different intervals from 1 to 16 h. The diffusion controlled character of crystallization predominates up to an extent of 61-62%. As an application, the grown crystals have been annealed and then employed as a photoanode and so copper tungstate crystal has been used to decompose water electrolytically. A higher EMF of 30 mV has been obtained. A three-electrode system containing the semiconducting photoanode and a calomel electrode placed in H2SO4/KCl electrolyte of pH 1.5 has been fabricated. (C) 2004 Elsevier B.V. All rights reserved.